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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Labrabaco: a G7 BC calculator from Labradar tracks
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<blockquote data-quote="ptosis" data-source="post: 2182809" data-attributes="member: 116258"><p>Following up on this interesting thread -- <a href="https://www.longrangehunting.com/threads/calculating-bc-with-labradar-it-works.202475/" target="_blank">https://www.longrangehunting.com/threads/calculating-bc-with-labradar-it-works.202475/</a></p><p></p><p>I have put together some code to calculate G7 ballistic coefficients from Labradar tracks. The tool is available here: <a href="https://bc.geladen.ch/labrabaco/labrabaco.html" target="_blank">https://bc.geladen.ch/labrabaco/labrabaco.html</a></p><p></p><p>It all runs in your browser, there is nothing to install, and it's free and open source.</p><p></p><p>Some bits of additional info are here: <a href="https://geladen.ch/en/labrabaco-v-0-5-beta-is-out/" target="_blank">https://geladen.ch/en/labrabaco-v-0-5-beta-is-out/</a></p><p>and here: <a href="https://geladen.ch/en/tips-to-set-up-labradar-for-the-most-awesomest-results/" target="_blank">https://geladen.ch/en/tips-to-set-up-labradar-for-the-most-awesomest-results/</a></p><p></p><p>My deepest gratitude goes to <strong>entoptics</strong><em>, </em>who provided absolutely precious data for design and calibration of the algorithms.</p><p></p><p>That is what can be expected:</p><p></p><table style='width: 100%'><tr><th>Bullet</th><th>ref BC</th><th>BC src</th><th>valid tracks</th><th>baco BC</th><th>diff, %</th></tr><tr><td>GP90 (Fass90)</td><td>0.166</td><td>CH armee</td><td>15</td><td>0.167</td><td>0.7%</td></tr><tr><td>GP11</td><td>0.274</td><td>CH armee</td><td>16</td><td>0.270</td><td>-1.4%</td></tr><tr><td>RUAG BALL 8.6</td><td>0.312</td><td>vendor [*]</td><td>7</td><td>0.316</td><td>1.1%</td></tr><tr><td>Lapua Scenar-L 7.62 155gr</td><td>0.230</td><td>vendor</td><td>16</td><td>0.230</td><td>0.1%</td></tr><tr><td>GP90 (SG-553-LB)</td><td>0.166</td><td>CH armee</td><td>14</td><td>0.166</td><td>-0.1%</td></tr><tr><td>Hornady ELDM 6.5 147gr</td><td>0.351</td><td>vendor</td><td>16</td><td>0.332</td><td>-5.4%</td></tr><tr><td>Berger EOL 6.5 156gr</td><td>0.347</td><td>vendor</td><td>4</td><td>0.352</td><td>1.3%</td></tr><tr><td>Hornady ELDM 5.56 73gr</td><td>0.200</td><td>vendor</td><td>5</td><td>0.206</td><td>3.0%</td></tr><tr><td>Hornady ELDM 6.5 147gr</td><td>0.351</td><td>vendor</td><td>5</td><td>0.337</td><td>-4.1%</td></tr><tr><td>Hornady ELDX 6.5 143gr</td><td>0.315</td><td>vendor</td><td>4</td><td>0.312</td><td>-1.0%</td></tr><tr><td>Hornady ELDX 7 175gr</td><td>0.347</td><td>vendor</td><td>19</td><td>0.353</td><td>1.6%</td></tr><tr><td>SMK 223 69gr</td><td>0.169</td><td>Litz [**]</td><td>10</td><td>0.167</td><td>-1.1%</td></tr><tr><td>Hornady ELDX 6.5 143gr</td><td>0.315</td><td>vendor</td><td>7</td><td>0.315</td><td>-0.1%</td></tr><tr><td>Hornady ELDX 7 175gr</td><td>0.347</td><td>vendor</td><td>22</td><td>0.351</td><td>1.2%</td></tr></table><p>[*] from trajectory data</p><p>[**] Applied Ballistics For Long Range Shooting, 2nd ed.</p><p></p><p>"Ref BC" is a known good G7 BC from "BC src". "Baco BC" lists the values calculated by labrabaco from radar tracks.</p><p></p><p>Gory details will follow in a separate article. In short, the software uses a 5th order polynomial regression weighted by SNR (absolute, not dB) on all data points for V(t), then runs an actual 3DOF ballistic engine in reverse to iterate to the best-fitting BC.</p><p></p><p>You're welcome <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile :)" loading="lazy" data-shortname=":)" /></p></blockquote><p></p>
[QUOTE="ptosis, post: 2182809, member: 116258"] Following up on this interesting thread -- [URL]https://www.longrangehunting.com/threads/calculating-bc-with-labradar-it-works.202475/[/URL] I have put together some code to calculate G7 ballistic coefficients from Labradar tracks. The tool is available here: [URL]https://bc.geladen.ch/labrabaco/labrabaco.html[/URL] It all runs in your browser, there is nothing to install, and it's free and open source. Some bits of additional info are here: [URL]https://geladen.ch/en/labrabaco-v-0-5-beta-is-out/[/URL] and here: [URL]https://geladen.ch/en/tips-to-set-up-labradar-for-the-most-awesomest-results/[/URL] My deepest gratitude goes to [B]entoptics[/B][I], [/I]who provided absolutely precious data for design and calibration of the algorithms. That is what can be expected: [TABLE] [TR] [TH]Bullet[/TH] [TH]ref BC[/TH] [TH]BC src[/TH] [TH]valid tracks[/TH] [TH]baco BC[/TH] [TH]diff, %[/TH] [/TR] [TR] [TD]GP90 (Fass90)[/TD] [TD]0.166[/TD] [TD]CH armee[/TD] [TD]15[/TD] [TD]0.167[/TD] [TD]0.7%[/TD] [/TR] [TR] [TD]GP11[/TD] [TD]0.274[/TD] [TD]CH armee[/TD] [TD]16[/TD] [TD]0.270[/TD] [TD]-1.4%[/TD] [/TR] [TR] [TD]RUAG BALL 8.6[/TD] [TD]0.312[/TD] [TD]vendor [*][/TD] [TD]7[/TD] [TD]0.316[/TD] [TD]1.1%[/TD] [/TR] [TR] [TD]Lapua Scenar-L 7.62 155gr[/TD] [TD]0.230[/TD] [TD]vendor[/TD] [TD]16[/TD] [TD]0.230[/TD] [TD]0.1%[/TD] [/TR] [TR] [TD]GP90 (SG-553-LB)[/TD] [TD]0.166[/TD] [TD]CH armee[/TD] [TD]14[/TD] [TD]0.166[/TD] [TD]-0.1%[/TD] [/TR] [TR] [TD]Hornady ELDM 6.5 147gr[/TD] [TD]0.351[/TD] [TD]vendor[/TD] [TD]16[/TD] [TD]0.332[/TD] [TD]-5.4%[/TD] [/TR] [TR] [TD]Berger EOL 6.5 156gr[/TD] [TD]0.347[/TD] [TD]vendor[/TD] [TD]4[/TD] [TD]0.352[/TD] [TD]1.3%[/TD] [/TR] [TR] [TD]Hornady ELDM 5.56 73gr[/TD] [TD]0.200[/TD] [TD]vendor[/TD] [TD]5[/TD] [TD]0.206[/TD] [TD]3.0%[/TD] [/TR] [TR] [TD]Hornady ELDM 6.5 147gr[/TD] [TD]0.351[/TD] [TD]vendor[/TD] [TD]5[/TD] [TD]0.337[/TD] [TD]-4.1%[/TD] [/TR] [TR] [TD]Hornady ELDX 6.5 143gr[/TD] [TD]0.315[/TD] [TD]vendor[/TD] [TD]4[/TD] [TD]0.312[/TD] [TD]-1.0%[/TD] [/TR] [TR] [TD]Hornady ELDX 7 175gr[/TD] [TD]0.347[/TD] [TD]vendor[/TD] [TD]19[/TD] [TD]0.353[/TD] [TD]1.6%[/TD] [/TR] [TR] [TD]SMK 223 69gr[/TD] [TD]0.169[/TD] [TD]Litz [**][/TD] [TD]10[/TD] [TD]0.167[/TD] [TD]-1.1%[/TD] [/TR] [TR] [TD]Hornady ELDX 6.5 143gr[/TD] [TD]0.315[/TD] [TD]vendor[/TD] [TD]7[/TD] [TD]0.315[/TD] [TD]-0.1%[/TD] [/TR] [TR] [TD]Hornady ELDX 7 175gr[/TD] [TD]0.347[/TD] [TD]vendor[/TD] [TD]22[/TD] [TD]0.351[/TD] [TD]1.2%[/TD] [/TR] [/TABLE] [*] from trajectory data [**] Applied Ballistics For Long Range Shooting, 2nd ed. “Ref BC” is a known good G7 BC from “BC src”. “Baco BC” lists the values calculated by labrabaco from radar tracks. Gory details will follow in a separate article. In short, the software uses a 5th order polynomial regression weighted by SNR (absolute, not dB) on all data points for V(t), then runs an actual 3DOF ballistic engine in reverse to iterate to the best-fitting BC. You're welcome :) [/QUOTE]
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